The presence of sulfur-containing substances or compounds (e.g., organic sulfur) in certain fluids, like carbonaceous fluids or solutions of hydrocarbons, may be undesirable. For example, sulfur in petroleum-based fluids may contribute to polluting air, water, soil, and the like, as the fluids are used and sulfur is potentially released into the environment. It may be desirable to reduce or remove the sulfur-containing compounds in, for example, fuels and oils before they are burned, combusted or otherwise used, and sulfur contained in the fluids is released.
Methods for removing or reducing the amount of sulfur-containing compounds in carbonaceous fluids are available. These methods may be called desulfurization methods. In one desulfurization method, called hydrotreating or hydrosulfurization, carbonaceous fluids and hydrogen may be treated at high temperature and pressure in the presence of catalysts. Sulfur may be reduced to H2S gas which then may be oxidized to elemental sulfur.
In another method, called oxidative desulfurization, sulfur-containing compounds may be oxidized and then removed from a fluid based on one or more properties of the oxidized sulfur-containing compounds. Oxidative desulfurization may use a variety of different oxidants as well as different conditions to initiate the oxidation reactions. In one example, sulfur-containing compounds in small volumes of a carbonaceous fluid may be oxidized using a peroxy oxidant in the presence of ultrasonic energy that produces cavitation bubbles in the fluid. This method of producing cavitation bubbles may be called acoustic cavitation.
Many of the methods for removing sulfur-containing compounds from carbonaceous fluids may be costly, may include harsh reaction conditions, may be unable to remove substantial amounts of sulfur-containing compounds, may be unable to remove sulfur-containing compounds having certain chemical structures, may not facilitate scale-up to large volumes of fluids, and so on.